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Macoun's Draba - Draba macounii
State Rank Reason (see State Rank above)
Known in Montana from only a few occurrences in Glacier National Park. Current population levels and trends are unknown. However, its high-elevation habitat is relatively inaccessible, and there are no obvious threats. Additional sites are likely to be documented.
- Details on Status Ranking and Review
Population Size
Score2-3 - Very Small to Small: Population size is imprecisely known but is believed to be <10,000 individuals.
Range Extent
Score1 - Peripheral, Disjunct or Sporadic Distribution in MT: Widespread species that is peripheral, disjunct or sporadically distributed within MT such that it occurs in <5% of the state (<7,500 sq. miles or the combined area of Beaverhead and Ravalli Counties) or is restricted to 4-5 sub-basins.
Area of Occupancy
Score2 - Low: Generally occurring in 4-10 Subwatersheds (6th Code HUC’s).
Environmental Specificity
Score1-2 - Moderate to High.
Trends
Score0-1 - Stable to Minor Declines:
CommentTrends unknown, though populations are likely stable or experiencing only minor declines.
Threats
Score0-1 - Low to Medium.
Intrinsic Vulnerability
Score1 - Moderate Vulnerability: Specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species susceptible to extirpation from stochastic events or other adverse impacts to its habitat and slow to recover.
Raw Conservation Status Score
Score
7 to 11 total points scored out of a possible 19.
General Description
Macoun's Draba is a low perennial herb with few to many leafless stems that are 1-4 cm high and which arise from leaf rosettes that, in turn, arise from the ends of a simple or branched rootcrown. The broadly lance-shaped leaves are 6-10 mm long and are glabrous to sparsely covered with branched hairs; the leaves have long straight hairs on the entire margins. The stalked flowers are borne at the tops of the stems in a compact inflorescence. Each flower has 4 separate sepals, 4 separate, white petals, and 4 long and 2 short stamens. The style is ca. 0.5 mm long. The glabrous, flattened, broadly elliptic capsules are 4-8 mm long and are borne on ascending or spreading stalks.
Phenology
Flowering in July.
Diagnostic Characteristics
There are many similar-appearing species of Draba in our area. A technical manual and hand lens or microscope are required for positive identification. The relatively broad leaves, compact inflorescence, and wide capsules help separate this species from D. lonchocarpa, a more common white-flowered species.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
AK to MT, and CO. Known from Flathead and Glacier counties (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations: 6
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Wet rock ledges and moist tundra in the alpine zone.
Ecological Systems Associated with this Species
- Commonly Associated with these Ecological Systems
Alpine Systems
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).
References
- Literature Cited AboveLegend:
View Online Publication- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
Lesica, P. and B. McCune. 1992. Monitoring the effects of global warming using peripheral rare plants in wet alpine tundra in Glacier National Park, Montana. Unpublished report to Glacier National Park, Research Division, West Glacier, Montana 59936. 55pp.- Lesica, P., K. Lackschewitz, J. Pierce, S. Gregory and M. O'Brien. 1986. Noteworthy collections: Montana. Madrono 33:310-312.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
- Mulligan, G.A. 1976. The genus Draba in Canada and Alaska: key and summary. Canadian Journal of Botany 54:1386-1393.
- Web Search Engines for Articles on "Macoun's Draba"
